What are the application scenarios of the SQL substring function?

The SUBSTRING function in SQL is used to retrieve a substring from a string, with possible use cases including:

1. Extracting a portion of a string: You can use the SUBSTRING function to extract a part of a string, such as someone’s last name or first name.
2. Extracting a part of a date or time: You can use the SUBSTRING function to extract parts such as year, month, day, hour, minute, etc. of a date or time field.
3. Splitting strings: You can use the SUBSTRING function to split a string with a specified delimiter and return the resulting substrings.
4. Replace a portion of a string: You can use the SUBSTRING function to replace a part of a string, such as replacing one word with another in a string.
5. Format string: You can use the SUBSTRING function to format a string according to a specified format, such as formatting a numeric string as currency.
6. Concatenate strings: You can use the SUBSTRING function to combine multiple strings together to create a new string.

The examples mentioned above are just some common scenarios for using the SUBSTRING function. In actual usage, there may be many more applications depending on the specific situation.